Circuit controlling device



Des. 31, 1935. w. M. sco'r'r, JR

CIRCUIT CONTROLLING DEVICE Filed May 24, 1934 4 Sheets Sheet 1 x 1 I i INVENTOR. EMZM 4L. My;

/1 TTORNEY.

W. M. SCOTT, JR

CIRCUIT CONTROLLING DEVICE Filed May 24, 1934 4 Sheets-Sheet 2 INVENTOR.

1 ATTORNEY.

1935 W. M. SQQTT, JR

CIRCUIT CQNTROLLING DEVICE Filed May 24, 1934 4 Sheets-Sheet 3 4 ATTORNEY.

W. M. sQQTT, m 7 2 25 7$1 CIRCUIT CONTROLLING DEVICE Filed may 24, 1954 4 Sheets-Sheet A INVENTOR.

aomlw; xlm

1 ATTORNEY.

Patented Dec. 31, 1935 UITED STATES PATENT FFI'SE CIRCUIT CONTROLLING DEVICE Application May 24, 1934, Serial No. 727,253

16 Claims.

My invention relates to automatic circuit breakers, and more particularly to circuit breakers which are non-closable or trip-free during continuance of abnormal circuit conditions.

In accordance with one aspect of my invention, the contact structure of the breaker is held closed in opposition to a powerful force by a latching system which is releasable by .a relatively li ht force, and which possesses insubstantial inertia; more specifically, the latching system ii cludes a latching element which countercr restrains somewhat less than all of the breaker-opening force and which of itself is incapable of preventing opening of the breaker, and another latching element which restrains the first latching element from movement by the small remainder of the breaker opening force.

More particularly, and for circuit breakers of the non-closable or trip-free type, the aforesaid latching system may serve disengageably to connect an operating member to the contact system of the breaker; preferably, the contact system, in moving to open-circuit position, releases latching structure or equivalent, normally holding the operating member against movement toallow resetting of the latching system.

My invention also resides in the features of combination, construction and arrangement hereinafter described and claimed.

For an understanding of my invention and illustration of various forms thereof, reference to be had to the accompanying drawings in which:

Figure 1 is a side elevational view with parts in section and parts omitted of a circuit breaker in closed circuit position;

Fig. la. is a front elevational view of a multipole circuit breaker;

Fig. 2 shows the parts of Fig. 1 after tripping;

Fig. 3 illustrates the parts of Fig. 1 after relatching preparatory for return to their positions of Fig. 1;

Fig. 4 is a detail view in plan, of a part shown in Figs. 1 to 3;

Fig. 5 is a side elevational view taken on line 5-5 of Fig. 4;

Figs. 6 to 9 illustrate another modification of the invention.

Referring to Fig. 1, the movable contact I carried by arm 2 supported by shaft 3 extending between brackets l bridges the fixed contacts 5, 5 on the front side of the base panel 6 of the circult breaker. For clarity, one of the brackets 4 is omitted. One end of an arm 1 is pivotally mounted on the pin 8 extending between the brackets and the other end of the arm carries a pin 9 upon which is mounted a link I 8 whose other end is pivoted at H to the contact-carrying arm 2.

One end of a link E2 is also carried by the pin 5 9, the other end of the link being pivotally connected, as by pin iii, to the arm M which is pivotally supported by shaft 15 extending between brackets 4. The powerful spring 16 connected between pin is and a suitable fixed point, as pin 10 3, tends to effect clockwise movement of arm 3' to effect circuit-opening movement of contact I. Under normal conditions, it is prevented from doing so by the novel latching arrangement now described. 15

Upon the lower end of arm 54 is pivotally mounted the latching member I l which is biased into engagement with the stop 58 as by the light spring id. The stop It, as indicated, is preferably a roller mounted for rotation on the pin 29 which 20 extends between the sides of the operating member 2|. The movement of latch ii is so limited, as by stop 22, or by the surface 2'3, that the latching shoulder 24 does not pass the line of centers between the axis of the roller i2 and the pivotal 25 axis 25 of the latch I1 and actually engages the roller slightly short of the line of centers so that although most of the force of spring 86 is restrained, there remains a component which tends to cause the latch IT to rotate clockwise about 30 its pivot 25, the shoulder 25 slipping along the surface of the roller and which, if unrestrained, would permit opening of the circuit breaker. In effect, the shoulder 24 and coacting surface of stop 58 engage in a plane slightly inclined with 35 respect to a plane normal to the line of action of the restrained force in a direction in which the latch is free to move, so that there is a component of the force on the latch tending to release it. 40

To the end of latch l l is pivoted a second, light latch 26 which is biased by spring 27 for counterclockwise movement about its pivot pin 28. The shoulder 29 of latch 26 engages the under surface of the stop or abutment 39 carried by the operating member 2 l. The pressure between the shoulder 29 and coacting surface of stop 30 is small since the only force acting on the second latch 26 is the small fraction of the force acting 50 on the main latch tending to cause it to slip. The coacting surfaces of the auxiliary latch and stop are preferably of hardened steel smoothed or polished to have small coefficient of friction.

The stop or latch plate 30 may be adjustable as by shims a to obtain a desired latching adjustment of the main latch.

The operating member 2| is held in the position shown by a third latch 3! which is pivoted thereon about pin 32 and adapted to engage the stop 33 secured to bracket 4, as by screws 34. This third latch does. not form part of the connection between the operating member 2! an the movable contact system.

The extension 35 of the auxiliary latch 26 is disposed adjacent the tripping member 35 which may be rocked manually about pin 3'? as by lever 39 or by the movable element of a device responsive to abnormal circuit conditions, for example, by the armature 49 of an electromagnetic overload trip, pivoted about the pin ll on the cam 42, having an extension 4-3 engaging, during overload, the projection 38 of the member 38.

The construction described has the advantage that only a small tripping force is required to open the breaker, making it particularly suited for large breakers where the problem'of controlling heavy forces with limited tripping forces is a serious one. Circuit breakers of this type have been built with large ampere capacities. Heretofore, it has been sought to increase the mechanical advantage by lever systems which expedient, however, was unsatisfactory, as the elements of such systems possess high inertia and they must accelerate rapidly due to their mechanical advantage.

With the construction illustrated only a slight force is required to effect disengagement of shoulder 29 of the auxiliary latch. When its restraint is removed, the main latch slips allowing spring it quickly to move the movable contact to open circuit position, the associated parts assuming the positions shown in Fig. 2. The tripping means need only furnish enough force to operate the latch 26, as release of this latch permits forces tending to release the main latch to become effective.

As the arm I4 approaches its'final open circuit position, the abutment 44 carried thereby en- 1 gages the upstanding arm 45 of latch 3i camming it for clockwise movement out of engagement with stop 33 to the position shown in Fig. 2. The cam surface 45a is of such contour, as shown, that the latch is released by a camming action rather than a sharp blow, and that the major movement of the cam is elfected during the initial contact with abutment 33 and relatively small movement occurs near the end,0f the motion.

To reclose the breaker, the member 2i, which may be arranged for operation by hand or a power device, is first swung upwardly toward the position shown in Fig. 3 to reset the latches. The spring i9 rotates the main latch i? to effect reengagement of shoulder 24 with roller I8 and .spring 2'! rotates the auxiliary latch 26 to effect reengagement between shoulder 29 and stop 3:). The member 25 thus reconnected to the movable contact system is then swung downwardly to restore the parts to the closed circuit position of Fig. 1, latch 3| hooking the stop 3-3 at the completion of the movement.

Preferably as shown, the main latch ll is provided with an arm Ila, which is engaged by the roller is as the lever 21 is swLmg to resetting position so that the latch is swung counter-clockwise about pin 25 into latching engagement with the roller. The cam surface llb of the main latch cooperates with roller 48 during resetting to prevent the secondary latch from looking be- .fore the main latch does.

The tripping member 35 extends adjacent to the path of the extension 35 of the auxiliary latch for a considerable distance from its final or closed-circuit position so that if there is an abnormal condition on the line, the circuit breaker 5 will trip immediately and cannot be held closed for any position of the operating member 2i.

The two latches in series form a disengageable connection between'the operating member 25 and arm M which can be easily broken by the auto- 10 matic tripping device for all positions of member 2! for which the fixed and movable contacts are in engagement.

In Fig. 1a, the operating arms 2| of three cirouit breakers are mechanically coupled by mem- 15 her 2 id so that all three are simultaneously closed by operation of the handle 2 lb, and all three can be manually tripped by rocking lever 39. Any number of breakers can be so mechanically coupled to provide a multi-pole breaker of the de- 20 sired number of poles.

Another modification of my invention is shown in Figs. 6 to 9 which, in general, is similar to the modification of Figs. 1 to 5. Parts identical with those of the previous modification, are identified 25 by the same reference characters, while parts slightly modified but having the same purpose are identified by the same reference number with addition of the modification letter E. For clarity, the links between the contact arm 2 and ac- 30.

tuatingarm ME, and latching members Si, 33 have been omitted.

In this modification, the arm ME is provided with an extension 50 havinga latching surface 5!. The primary latch 53 which is pivotally 35 mounted on the operating arm HE is provided with a hooked end which engages surface 5! to latch the operating arm ME to actuating arm ME. Stop 55 of latch 53 limits engaging motion of the latch about its pivot 56. 40

On extension 51 of the latch is pivotally mounted the secondary latch 58 having a thrust surface 29 engaging the plate 35 of arm ZlE to resist clockwise unlatching movement of latch 53. Stop 59 of the secondary latch limits its'counter- 45 clockwise movement by spring 2? which is attached to arm 60 of the main latch.

Disengagement of the secondary latch 58 is effected when the tripping member 36 moves the finger 35E of tripping arm 32 in clockwise direcso tion so that lug 6| thereof engages and rocks the secondary latch about its pivot 28 (Fig. 6). Just after the surface 29 of the latch has cleared the plate 30, the tail 64 of the latch strikes the stop pin 65 so that the kinetic energy of the secondary latch produces an upward reaction on pin 28 to accelerate the disengagement of main latch 53 against the bias of spring i9. The breaker is in closed circuit condition when the parts are in the full line position of Fig. 6, 60 the latches resisting the opening force of a spring such as, for example, spring l6 of Fig. 1. The angle of the main latch surface 5! is such that they tend to disengage when subjected to contact load; the slipping component is sufficient to 65 overcome the bias of'spring 9. The resultant of the slipping force and the bias of spring i9 is resisted by the secondary latch.

When the tripping member 35 operates to disengage-the secondary latch, the slipping component of the main latch produces upward movement of pin 28 and secondary latch 58. The tripping impulse of 35 imparts a velocity to members 58 and 62 which, by the action of tail 6% against pin 65, is utilized to pry open the main latch. This action is cumulative with the slipping action of the main latch and reduces the time between the response of armature 40 and open circuit position of the breaker contacts. Reduction of tripping time is also enhanced by separation of tripping finger 35E from the secondary latch (see Figs. 1 and 6) and pivoting it separately on arm ZIE at 66, thus reducing the inertia of the latch system,

Upon tripping, the main latch and arm ME assume the positions shown in dotted lines in Fig. 6. Arm ME and contact 2 move from the position shown in Fig. '7 to positions corresponding to the open-circuit position of the similar elements of Fig. 3. The arc-shaped guard finger 52 maintains the main latch in trip position preventing re-engagement of the secondary latch until after the main latch has been returned to holding position.

To reclose the breaker, arm HE is first raised to a position corresponding to the position of arm 2| in Fig. 3 to effect re-engagement of the main latch. As the extension 50 of arm ME passes beyond the guard finger 52, spring 2'! resets the secondary latch completing the mechanical connection between the operating arm 2i E and the actuating arm ME. Arm ZIE is then moved downwardly to the position shown in Fig. 6 to close the breaker contacts and is latched in position by parts 3|, 33 of Fig. 1 or equivalent.

The breaker is of the trip-free type, since, if abnormal conditions exist when the contacts engage, the latches will release the actuating arm ME, permitting the breaker to open even though arm 2 E is restrained in its down position.

It is characteristic of the modifications that a series of latches is interposed between the tripping means and the movable contact system, the final latch being sensitive or easily releasable and restraining a slip latch more adjacent the movable contact system which is more rugged and restrains a substantial part of the breaker-opening force.

While I have illustrated two preferred constructions, my invention is not limited thereto, but is co-extensive in scope with the appended claims.

What I claim is:

l. A circuit-controlling device comprising movable contact structure, a system for operating said contact structure, means for biasing. said contact-structure to one circuit position, tripping means, and means for releasably holding said contact structure in a second circuit position against the force of said biasing means comprising a latching arrangement ca-ried by said contact operating system and having a component restraining all but a small fraction of said force which fraction tends to effect releasing movement of said component, and having another component for restraining said first component from movement, and releasable by said tripping means, said components including means for accelerating said first component in response to the tripping force effecting release of said second component.

2. A circuit-controlling device comprising movable contact structure, a system for operating said contact structure, means for biasing and contact structure to one circuit position, tripping means, means for releasably holding said contact structure in a second circuit position against the force of said biasing means comprising a latching system having a component restraining all but a small fraction of said force which fraction tends to eifect releasing movement of said component, another component for restraining said first component from said movement and releasable by said tripping means, and resilient means carried by said contact-operating system for resetting said latching system for movement of said contact structure to said second circuit position.

3. A circuit breaker comprising a movable con- 10 tact system including a pivoted element, means for biasing the contact structure to open-circuit position, tripping means responsive to abnormal circuit conditions, a pivoted member carried by said element and engaging a stop to restrain nearly all of the force of said biasing means, the remaining fraction tending to eiTect pivotal movement of said member from said stop, a latch member pivotally mounted on said pivoted member to restrain said movement thereof until said tripping means releases said latch member.

4. A circuit-controlling device comprising movable contact structure. a system for operating said contact structure, means for biasing said contact structure to open-circuit position, means for releasably holding said contact structure in closed circuit position comprising latches carried by said contact-operating system and connected mechanically in series, one of said latches restraining substantially all of the force tending to effect circuit-opening movement of said structure, and the other of said latches normally re straining said first latch, and tripping means for releasing said other latch and for increasing the acceleration of said one of said latches.

5. A circuit breaker comprising movable contact structure, means for biasing said contact structure toward open circuit position, tripping means, operating structure, means releasably connecting said contact structure to said operating structure comp 'ising latches movable with said contact structure, one of which restrains substantially all of the force tending to effect circuitopening movement of said contact structure, and the other of which, releasable by said tripping 15 means, restrains said first latch, and a third latch for releasably holding said operating structure in its closed position.

6. A circuit breaker comprising movable contact structure, means for biasing said contact structure toward open-circuit position, tripping means, operating structure, means releasably connecting said contact structure to said operating structure comprising latches movable with said contact structure, one of which restrains substantially all of the force tending to effect circuitopening movement of said contact structure, and the other of which, releasable by said tripping means, restrains said first latch, and a third latch normally holding said operating structure in its on closed position released substantially upon com pletion of circuit-opening movement of said contact structure.

7. A circuit breaker comprising movable contact structure, means for biasing said contact structure to open-circuit position, tripping means responsive to abnormal circuit conditions, operating structure, and means for releasably connecting said contact structure to said operating structure comprising members movable concurrently with movement of said contact structure, each engaging said operating structure, and one of which is actuatable by said tripping means to effect disengagement of said members from said operating structure.

8. A circuit breaker comprising a movable contact system including a pivoted arm, means for biasing said system for circuit-opening movement, tripping means, an operating system including a lever pivoted concentrically with said arm and having two abutments, and means releasably connecting said systems comprising two latches mechanically connected in series and carried by said arm, one or" said latches engaging one of said abutments to restrain substantially all of the force tending to effect circuit-opening movement of said contact system and the other of said latches, releasable by said tripping means, normally restraining said first latch from movement by the remainder of said force.

9. A circuit-controlling device comprising movable contact structure, means ior biasing said contact structure to one circuit position, an actuating member for moving said contact structure to another circuit position, a main latch carried by said member and engaging a fixed abutment to restrain all but a small fraction of the force of said biasing means, a secondary latch carried by said latch and engaging a fixed abutment to restrain said main latch from movement by said fractional force, and tripping means for releasing said secondary latch.

10. A circuit controlling device comprising movable contact structure, means for biasing said structure to open circuit position, an actuating member for moving said structure to another circuit position, an operating member releasably connected to said actuating member, a main latch carried by said actuating member and engaging a fixed abutment on said operating member to restrain all but a small fraction of the force of said biasing means, a secondary latch carried by said main latch and engaging another fixed abutment on said operating member to restrain said main latch from movement by said fractional force, and tripping means for releasing said secondary latch.

11. In a circuit controller having pivoted contact structure biased to open circuit position, an

1 operating member, latching means releasably 1 bias, and cam means for releasing said third latch during initial movement of contact struc ture toward open circuit position.

12. In a circuit controller having pivoted contact structure biased to open circuit position, an

operating member, latching mechanism releasably connecting said structure and said member comprising a main latch engaging a first abutment to retain all but a fraction of the force of said bias, a secondary latch pivotally mounted on said main latch and engaging a second abutment to restrain said main latch, and means to cause positive engagement of main latchduring relatching comprising an extension on said main latch cooperating with said first abutment.

13. In a circuit controller having pivoted contact structure biased to open circuit position, an operating member, latching mechanism releasably connecting said structure and said member comprising a main latch engaging a first abutment to restrain all but a fraction of the force of said biasing means, a secondary latch pivotally mounted on said main latch and engaging a second abutment to restrain said main latch, means for preventing engagement of the secondary latch until after engagement of the main latch, and tripping means for releasing said sec ondary latch.

14. In a circuit controller having pivoted conondary latch.

15. In a circuit controller having pivoted contact structure biased to open circuit position, an o crating member, latching mechanism releasably connecting said structure and said member comprising a main latch engaging a first abutment to restrain all but a small fraction of the force of said bias, a secondary latch pivotally mounted on said main latch and engaging a second abutment to restrain said main latch, means for adjusting the position of the second abutment, and tripping means for said secondary latch.

16. A circuit-controlling device comprising pivoted contact structure, means for biasing said contact for rotation to one circuit position, a pivotally mounted actuating member for rotating said contact structure to another circuit position, a main latch pivotally mounted on said member and engaging a fixed abutment to restrain all but a fraction of the force of said biasing means, a secondary latch pivotally mounted on said main latch and engaging a fixed abutment to restrain said main latch, and tripping means for releasing said secondary latch.

WILLIAM M. SCOTT, JR.

Patent No. 2,025,781. December 51, 1955.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 65, claim 1, strike out the comma after Movement; and line Leslie Frazer (Seal) Acting Commissioner of Patents.

Patent No. 2, 025,781 December 51 1955.

WILLIAM M. SCOTT, JR.

the above numbered patent requiring correction as follows: Page 3, first column, line 65, claim 1, strike out the comma after "movement"; and line 70, claim 2, for "and" read said; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record Leslie Frazer (Seal) Ac g mmi oner f Patents. 

